Journal of Alzheimer's Disease - Volume 11, issue 1

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ISSN 1387-2877 (P)

ISSN 1875-8908 (E)

Impact Factor 2019: 3.517

The Journal of Alzheimer’s Disease is an international multidisciplinary journal to facilitate progress in understanding the etiology, pathogenesis, epidemiology, genetics, behavior, treatment and psychology of Alzheimer’s disease.

The journal publishes research reports, reviews, short communications, book reviews, and letters-to-the-editor. The journal is dedicated to providing an open forum for original research that will expedite our fundamental understanding of Alzheimer’s disease.

Abstract: Pin1 protein, a peptidyl-prolyl cis-trans isomerase plays an important regulatory role in neuronal function. Recent studies indicate that Pin1 may promote the dephosphorylation of tau and restore its ability to bind to and polymerize microtubles. Previous studies on postmortem human brains showed that Pin1 is down-regulated in advanced Alzheimer's disease (AD) brains compared to age-matched non-demented controls. Because AD is a slowly progressive disease with a preclinical period that can last years, the abundance and regulatory function of Pin1 may vary on the course of the disease. In order to evaluate the potential contribution of Pin1 to AD pathogenesis, levels…of mRNA, protein and isomerase activity of Pin1 and phosphorylated tau from postmortem brains of 10 persons with mild-cognitive impairment (MCI), 10 with AD and 10 age-matched no cognitive impairment (NCI) were measured. The relationship between Pin1 and phosphorylated tau as well as clinical and cognitive data were analyzed. The results indicated that Pin1 activity in MCI and AD were significantly higher than in NCI. Phosphorylated tau in MCI and AD was also higher than in NCI group. The positive correlation trend in MCI and the robust correlation in AD between Pin1 activity and phosphorylated tau implies that increasing phosphorylated tau during AD pathogenesis may induce the compensatory activation/up-regulation of Pin1, while the inverse correlation between Pin1 activity and phosphorylated tau in NCI group implies that decreased Pin1 may play a role in the initial accumulation of phosphorylated tau in AD pathogenesis.
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Abstract: Background: The concept that the neurotoxicity of amyloid β protein could partly result from vascular effects that may be detected in peripheral microcirculation is new. Methods: We compared peripheral endothelial vascular responses of patients with early clinically confirmed Alzheimer’s disease (AD) to that of people with normal cognition and those with other forms of dementia. Acetylcholine (ACh) was iontophoresed into the skin and the resultant vasodilator response was measured using laser Doppler flowmetery. Results: The ratio of ACh response to saline (ratio E/S) was determined. Mean ± SEM of ratios E/S were 8.8 ± 0.9…for controls (n = 168 ), 1.4 ± 0.1 for AD patients (n = 80 ) and 3.1 ± 0.5 for other dementia (n = 84 ). Using the optimal cut-off point of E/S ratio of 1.9, an 80% diagnostic sensitivity and specificity for AD have been observed. When the control sample was filtered for those with cardiovascular diseases and with MMSE < 28, this improved the specificity to 90% (n = 119 ). Furthermore, 15 subjects were randomly drawn from a longitudinal healthy ageing study. Five of those subjects met the criteria for mild cognitive impairment (MCI) after eight years of follow up using a battery of cognitive tests. When tested for their E/S ratio in a blind fashion, the skin test successfully identified those subjects. Conclusions: The results support our hypothesis that endothelial alterations can be detected early in the course of the disease. We suggest that this simple skin test could potentially be applied as diagnostic adjunct in patients with mild cognitive symptoms or those with early clinical evidence of AD.
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Abstract: Metal ions are widely recognized as a key factor for the conformational changes and aggregation of the Alzheimer's disease amyloid (Aβ). So far Al3+ has received much less attention than other biometals in terms of interaction with Aβ. Brain endothelial cells have been identified as important regulators of the neuronal microenvironment, including Aβ levels. The purpose of this study is to compare the effects of the complex amyloid (Aβ1-42 )-Al, from human and rat, with the effects produced by metal-free Aβ on rat neuroendothelial cells (NECs). To establish Aβ and Aβ-Al toxicity on NECs, survival, vitality, and angiogenesis are…evaluated. Cell survival is reduced by human and rat Aβ in a time-dependent manner. This toxic effect is remarkably pronounced in the presence of human Aβ-Al. Moreover, rat Aβ has anti-angiogenic properties on NECs, and this effect is aggravated dramatically by using both human and rat Aβ-Al complexes. The data and arguments presented herein clearly demonstrate the involvement of Al3+ in Aβ aggregation and, consequently, increasing endothelial cell toxicity.
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Abstract: Rosiglitazone was found to simulate mitochondrial biogenesis in mouse brain in an apolipoprotein (Apo) E isozyme-independent manner. Rosiglitazone induced both mitochondrial DNA (mtDNA) and estrogen-stimulated related receptor alpha (ESRRA) mRNA, a key regulator of mitochondrial biogenesis. Transcriptomics and proteomics analysis suggested the mitochondria produced in the presence of human ApoE3 and E4 were not as metabolically efficient as those in the wild type or ApoE knockout mice. Thus, we propose that PPARγ agonism induces neuronal mitochondrial biogenesis and improves glucose utilization leading to improved cellular function and provides mechanistic support for the improvement in cognition observed in treatment of Alzheimer's…patients with rosiglitazone.
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Abstract: Autopsied brain tissue from Alzheimer's disease patients and old non-demented controls was studied after immunocytochemistry with the 4G8 monoclonal antibody that recognizes amyloid-β peptides. Intraneuronal 4G8-positive reaction product was detected in all of the studied brains. The same brain regions in the Alzheimer's disease samples consistently showed both more immunopositive neurons and more stained reaction product per neuron than those from the non-demented brains. Ultrastructurally, the immunopositive reaction product accumulated in clusters of cytoplasmic elements that had a lipofuscin-like appearance, showed a fibrogranular content and were also closely apposed to lipid droplets located either on their periphery or within them.…The most strongly 4G8-immunopositive elements had diffuse limits with their fibrogranular content free in the cytoplasm, whereas elements either without or showing only light immunoreaction had a limiting membrane. All immunopositive neurons displayed a similar pattern of clumping heterochromatin. The hypothetical neurotoxic role of intraneuronal amyloid-β peptides free in the cytoplasm is discussed as is the possible relationship between the amyloid-β peptides recognized by the 4G8 antibody and the lipid droplets which would presumably contain esterified cholesterol.
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Abstract: Adults with Down syndrome (DS) develop Alzheimer disease (AD) pathology progressively with age but clinical signs of dementia are delayed by at least 10 years after the first signs of disease. Some individuals with DS do not develop dementia despite extensive AD neuropathology. Given the discordance between clinical decline and AD neuropathology, compensatory events may be of particular relevance for this group. Imaging studies using PET suggest compensatory increases in metabolic rate in vulnerable brain regions in DS prior to the development of dementia. Neurobiological studies of similarly aged DS autopsy cases provide further evidence of activation of plasticity mechanisms.…Genes that are overexpressed in DS (APP, DSCAM, MNB/DYRK1A, and RCAN1) produce proteins critical for neuron and synapse growth, development and maintenance. We present the hypothesis that these genes may lead to developmental cognitive deficits but paradoxically with aging, may participate in molecular cascades supporting neuronal compensation. Enhancing or supporting compensatory mechanisms in aging individuals with DS may be beneficial as suggested by intervention studies in animal models. In combination, adults with DS may be a unique group of individuals well-suited for studies involving the manipulation or upregulation of compensatory responses as an approach to promote successful brain aging in the general population.
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